Periodontal bacteria in adult twins

Background: Both environmental and genetic factors are known to influence c linical measures of periodontal disease. The purpose of this study was to d etermine whether genetic factors similarly influence the presence of specif ic periodontal bacteria in subgingival plaque. Methods: Reared-together and reared-apart monozygous (MZ) and dizygous (DZ) adult twins were examined clinically. Demographic and behavioral informati on was obtained from each subject by questionnaire. Subgingival plaque samp les were obtained from the index teeth, and the presence of P. intermedia, P. gingivalis, A. actinomycetemcomitans, E. corrodens, and E nucleatum was determined using an immunoassay. Results: Microbiological and clinical data were available for 169 twin pair s. The subject-based prevalences of the bacteria in the twin groups ranged from 11% for Porphyromonas gingivalis to 40% for E nucleatum. For all speci es examined, the concordance rates were not significantly different (P >0.0 5) between MZ and DZ twin groups. These findings were apparent despite simi lar smoking histories, self-reported oral hygiene practices, and antibiotic use in the twin groups. Furthermore, MZ twins reared together were not mor e similar than MZ reared-apart twins with respect to any bacterial species examined. Conclusions: These findings suggest that in a population with access to rou tine dental care, any effects that host genes and the early family environm ent have on the presence of specific bacteria in subgingival plaque are not apparent in adulthood. Most twins with disease in this study had early per iodontitis. Results from this study may not necessarily be extrapolated to more advanced disease states.